The present invention relates to a catheter, and to a method for manufacturing a catheter, for example, a catheter with one or more electrodes or a heating element formed on a surface thereof. The invention also relates to an assembly for use in the manufacture of a catheter.
Catheters having one or more electrodes formed on a surface thereof or a heating element formed on a surface thereof are known. Such catheters may be plain catheters, or balloon catheters. Catheters which are provided with electrodes formed on an outer surface thereof are typically provided to facilitate measuring of a transverse cross-sectional dimension or a volume of a vessel or lumen in which the catheter is located in a human or animal body, such as a blood vessel, a cavity of the heart, the stomach, the urethra, the oesophagus, the intestine, and other such vessels, lumens and organs. Alternatively, the electrodes may be provided for facilitating ablating of tissue in a vessel or lumen by passing an electric current or a high frequency signal through the tissue from one electrode to another. Where such catheters are provided with a heating element, the heating element may be used also for ablating tissue by heating.
In general, where such catheters, either balloon catheters or plain catheters, are provided with electrodes for measuring a transverse cross-sectional dimension or the volume of a vessel or lumen, the electrodes typically are located at a distal end of the catheter in spaced apart relationship relative to each other, and typically, are formed by band electrodes extending around the catheter. The two outermost electrodes are provided as stimulating electrodes to which a stimulating electric current is applied, and the electrodes located between the outermost electrodes are sensing electrodes on which a voltage response signal is developed when the stimulating electric current is applied to the stimulating electrodes, and the catheter is located in the vessel with an electrically conductive medium present in the vessel. The voltage response signals developed on the sensing electrodes are indicative of an adjacent transverse cross-sectional dimension of the vessel or lumen. Alternatively, when the catheter is provided in the form of a balloon catheter, the electrodes are located on the catheter within the balloon, and the balloon is inflated with an electrically conductive medium. The voltage response signals developed on the sensing electrodes in response to an electric current signal applied to the stimulating electrodes are indicative of an adjacent transverse cross-sectional dimension of the balloon. Such catheters, be they plain catheters or balloon catheters, will be known to those skilled in the art.
Catheters which are provided for ablating tissue in a vessel, lumen or organ of a human or animal body ablate the tissue by applying an electric current through the tissue or subjecting the tissue to a high frequency current signal. In general, such catheters are of similar construction to those for measuring a transverse cross-sectional dimension or volume of a vessel or lumen. In the case of catheters which are provided with a heating element, the heating element, in general, is provided by an electrically resistive track which is formed towards the distal end of the catheter. By passing an electric current through the electrically resistive track, heat is generated.
In all such catheters, be they balloon catheters or plain catheters, or be they of the type for measuring a transverse cross-sectional dimension of a vessel or lumen, or for ablating tissue in a vessel or a lumen, are provided with electrodes or a heating element or heating elements on an outer surface of the catheter. The electrodes or heating elements must be coupled to corresponding ones or pairs of mutually electrically insulated electrically conductive wires, which in general extend through a lumen of the catheter from the electrodes or heating elements to the proximal end of the catheter for coupling to suitable electronic control and analytical equipment.
The manufacture of such catheters, be they balloon catheters or plain catheters, is quite a complex, tedious and time consuming task. Firstly, the electrodes or heating elements must be secured to the outer surface of the catheter, which is a tedious and time consuming task. Secondly, the electrically conductive wires which are to be coupled to the electrodes or heating elements must first be passed through a lumen in the catheter from the proximal end thereof, and urged through one or more radially extending openings from the lumen adjacent the electrodes or heating elements. The wires must then be electrically connected by either soldering or by an electrically conductive adhesive to the corresponding electrodes or heating elements. This is also a tedious and time consuming task, and there is also the risk of the wires being coupled to the incorrect ones of the electrodes or heating elements.
There is therefore a need for a method for manufacturing a catheter which addresses the problem of producing catheters known heretofore, be it a plain catheter or a balloon catheter.
The present invention is directed towards providing such a method, and the invention is also directed towards providing a catheter and a balloon catheter. The invention is also directed towards an assembly for use in the manufacture of a catheter.